1. Field of the Invention
The present invention relates to an internal combustion engine with a breather chamber for a breather that provides a flow of blow-by gas backward to an intake path.
2. Description of Background Art
An internal combustion engine is disclosed in JP-A No. 2006-283578 wherein an operation control unit (e.g., hydraulic control valve device) for controlling the operation of an operation control mechanism (e.g., hydraulic cylinder stop mechanism), which controls an engine operating state, and a breather chamber wall for forming a breather chamber are positioned so as to protrude from the outer surface of a cylinder head cover that constitutes an engine main body.
Not only the breather chamber wall, which forms a breather chamber, and the hydraulic control valve device but also a secondary air supply device 90 for an exhaust system, an ignition coil 31 integral with a spark plug 30, an engine status sensor, and other components are positioned on the outer surface of the cylinder head cover, which constitutes the engine main body together with a cylinder block and cylinder head. Therefore, these components need to be compactly arranged within a limited space.
Meanwhile, the breather chamber is capable of separating oil that is mixed with a blow-by gas. To enhance the oil separation efficiency, it is preferred to increase the capacity of the breather chamber. However, the space above the cylinder head cover is limited while various components are positioned on the cylinder head cover as described above. Therefore, it is difficult to increase the capacity of the breather chamber due to the limitations imposed by the other components. If an attempt is made to avoid interference with the other components and increase the capacity of the breather chamber, it is necessary to enlarge the cylinder head cover or the breather chamber wall protrudes out of the cylinder head cover, making it difficult to compactly set the cylinder head cover.
In addition, internal combustion engine parts (air cleaner, etc.) and parts for devices other than the internal combustion engine may be positioned above the cylinder head cover. Therefore, the upward protrusion of the breather chamber is limited.